I smoke marijuana and did a hair follicle test, it came back negative, why?

Asked Jul 25, 2012, 11:29 PM
—
2 Answers

I smoke a hit or two a day, maybe... I did a follicle test and it came back negative. I would assume that even though it's only a few hits a day it is still frequently enough to show a positive. What gives?

I smoke a hit or two a day, maybe... I did a follicle test and it came back negative. I would assume that even though it's only a few hits a day it is still frequently enough to show a positive. What gives?

The main reason is that hair is a very poor medium for detecting THC metabolites. Far less apt to detect infrequent and low level cannabis use than urine drug testing.

It may ultimately incorporate into your hair in sufficient quantity to be detected simply due to accumulation or it may not as even chronic heavy users are detected at only around 60%.

Hair drug testing is also heavily influenced by ethnicity and hair color.

Doesn't correspond with the claims of commercial testing labs in promoting the procedure but is well documented.

Ref. “Basic drugs such as cocaine and methamphetamine concentrate in hair due to ionic bonding to melanin, the pigment in hair that determines hair color. The more neutral and lipophilic THC is not strongly bound to melanin, resulting in much lower concentrations of THC in hair as compared to other drugs of abuse. " [183-186].
Marilyn A. Huestis (2007) Human Cannabinoid Pharmacokinetics. Chem Biodivers. 2007 August; 4(8): 1770–1804. Sec 3.5

Add your answer here.

Check out some similar questions!

My son has never done any type of drugs before, he went to the beach this past summer and tried Marijuana. He said he only took 3 puffs and never tried it again. It has been about 75 days and he has to have a hair follicle drug test, would that be enough to show up in it? He is so worried.

My ex smokes marijuana and I'm trying to get a really good job, so I don't want to be around him smoking it because I'm scared it will be found in the hair follicle drug test this employer uses. But, I miss hanging out with my friends because they also are avid pot smokers. Can I be around others...

My son has to take a hair follicle in mid January he was in a rehab for 7 months and got out in sept. he relapsed but did not smoke much maybe a blunt and couple joints from what I understand but nothing since beginning of December will it show up:(